ceph-go example: create rbd volume with image features

rbd-create.go

func createRBDStorage() error {
	// Runs the equivalent of rbd --pool ffledgling-pool ls
	// Contains basic connection logic that's reusable
	
	log.Println("Function started...") // We have this because connection setup etc take a while.

        // If like me, you tried this first and expected it to work, it doesn't:
	/*
        	conn, _ := rados.NewConn()
        	args := []string{"--name", "client.ffledgling", "--conf", "/home/ffledgling/ceph.conf"}
        	conn.ParseCmdLineArgs(args)
	*/
	
	conn, _ := rados.NewConnWithUser("ffledgling")
	conn.ReadConfigFile("/home/ffledgling/ceph.conf")
	
	if err := conn.Connect(); err != nil {
                log.Fatalln("Connection Failed.", err)
		return err
        }

	/*
         * We also pass rbd image options set to 1, which enables *only* layering.
         * Follow up reading:
         * Explanation of features: http://tracker.ceph.com/issues/15000
         * Slightly user-friendly blog post: https://www.sebastien-han.fr/blog/2015/07/06/ceph-enable-the-object-map-feature/
         */

        iox, err := conn.OpenIOContext("ffledgling-pool")
        image, err := rbd.Create(iox, "go-test-vol", 1024*1024*1024*100, 22, 1)
        if err != nil {
                log.Println("RBD image creation failed", err)
                return err
        }

	// Check the volume was created.
        vols, err = rbd.GetImageNames(iox)
        if err != nil {
                log.Println("IOX:", err)
		return err
        }

        for i, e := range vols {
                log.Println(i, e)
        }

        // Clean up after ourselves.
        image.Close()
        iox.Destroy()
        conn.Shutdown()

        return nil
}